The project's purpose is to define the biochemical composition of the major surface constituents of Bordetella pertussis and their relationship to the pathogenicity and epidemiology of whooping cough. Techniques have been developed which allow for the controlled selection, from a single strain, of the three major, stable phenotypes of B. pertussis. Isogenic sets of cloned phenotype variants are compared for differences in SDS-PAGE profiles after Coomassie brilliant blue staining for protein, extrinsic labeling by 125Iodine and/or silver staining for lipopolysaccharide. The three phenotypes possess characteristic SDS-PAGE profiles, colonial morphologies on BGA, growth characteristics on nutrient agar and antibiotic and oleic acid sensitivity profiles. Lipopolysaccharide variants have been characterized and their role in phenotype dynamics was studied. Two lipopolysaccharide types have been defined, isolated, and characterized chemically and immunologically. Analysis of specific mutants and their products can better define the genetic basis of virulence in B. pertussis for furthering understanding of pathological and immunological mechanisms of whooping cough.